Ecological energetics of the seaweed zone in a marine bay on the Atlantic coast of Canada. I. Zonation and biomass of seaweeds

✍ Scribed by K. H. Mann

• Publisher: Springer-Verlag
• Year: 1972
• Tongue: English
• Weight: 915 KB
• Volume: 12
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00347424

✦ Synopsis

An intertidal and underwater survey of the zonation of seaweed in St. Margaret's Bay, Nova Scotia, Canada showed 8 major zones as one proceeded away from shore: (1) l~ucus and Ascophyllum; (2) Chorda with filamentous browns; (3) Chondrus crispus; (4) Zostera marina; (5) Laminaria digitata with L. longicruris; (6) Laminaria longicruris; (7) L. longicruris with Agarum cribrosum; (8) Agarum cribrosum with Ptilota serrata. Zostera occurred at the same level as C. crispus but replaced it in sheltered water. Ascophyllum was more abundant in sheltered water. L. digitata was confined to the more exposed, steeper shore. The average horizontal extent of the seaweed zone was 369 m, and the greatest depth of significant amounts of seaweed 20 to 30 m. Laminarla longicruris contributed 36 % of the total biomass, and Laminaria spp. and Agarum together constituted 83 %, while intertidal seaweeds contributed less than 10% of the biomass. The estimated average total biomass per m of shore line was 1,481 kg fresh weight, 326 kg dry weight, 98 kg carbon, or 980 x I0 a kcal. When averaged over the whole area of the bay, the corresponding figures were L38 kg/m 2 fresh weight, 0.30 kg/m ~ dry weight, 91 g/m 2 carbon or 912 kcal/m 2. Dry matter of Laminaria was 15 to 27% of fresh weight in blades, 10 to t2% in stipes. The dry matter content of blades was least in spring and highest in autumn, but carbon content and calorific value of dry matter showed little difference with species or season. * Contribution to the International Biological Programme CCIBP 108. ** Bedford Institute Contribution BI 249.